Update June 12, 2011: Added a link to and excerpt from commentary by David Hembrow, a British blogger in the Netherlands.

How does a 3-way street work? Easy, just watch the video.

I like the term “aggressive yield” to describe the situation when a motorist does yield to pedestrians crossing the street, but in a way where they inch forward continually, slowly pushing, with a buffer or air, the people out of the way.

those red markers are just showing the limits of tolerable risk as established by years of system development. If the collision speeds were higher, those red circles would be far few – it’s simply a system finding its own point of stability.

If you really want to wreak havoc – try to control that system without corrective feedback (eg more rules, lights, controls, etc) and you’ll see the system kill people while it tries to find new stable relationships.

don’t forget that rules, signs, lights, etc have no direct impact on the system – they only work through the interpretation of the users.

I don’t see the behaviour at this junction as being about “bad habits”. What I see is simply a very badly designed junction which almost invites people to behave in the way that they do.

Dutch road junctions don’t look like and work like this – they are different for a reason: it removes the conflicts and improves safety. A long-standing theme of Dutch road design is the concept of Sustainable Safety. The concept is to remove conflict so that collisions are rare and the consequences of those which remain are relatively small. Roads are made self-explanatory so that bad behaviour is reduced and the way people behave is changed.

Reading this reminds me of the work of the students in George Aye’s class at SAIC, “Living in a Smart City.” The students attempted, through an intersection redesign, to reduce the stresses that lead to crashes.

Where are the 3-way streets in your city? Grand/Halsted/Milwaukee in Chicago comes to my mind easily. Also a lot of streets in the Loop. Oh yeah, and The Crotch, at Milwaukee/North/Damen.